{% assign baseurl = site.baseurl | append: include.sidebar.url %}
<h4 class="sidebar-title">{{include.sidebar.title}}</h4>
<ul class="sidebar-links">
   {% for item in include.sidebar.links %}
      {% assign url = include.sidebar.url | append: item.url %}
      {% if url == page.permalink %}
         {% assign class = "active" %}
      {% else %}
         {% assign class = "" %}
      {% endif %}
      <li><h6 class="{{class}}"><a href="{{baseurl}}{{item.url}}">{{item.title}}</a></h6></li>
   {% endfor %}
</ul>
